Oilfield operations may be performed to locate and recover downhole fluids, such as oil and gas. Oil rigs can be positioned at well sites, and downhole tools or other drilling tools can be deployed into the ground to reach subsurface reservoirs. Once the downhole tools form a wellbore to reach a desired reservoir, casings may be placed within the wellbore and the wellbore completed to initiate production of fluids from the reservoir. Downhole tubular devices, such as pipes, downhole tools, casings, coiled tubing, or other tubular members, and associated components, such as drill collars, tool joints, drill bits, logging tools, packers and the like (which can be referred to as “tubulars” or “tubular strings”) may be positioned in the wellbore for allowing the passage of subsurface fluids to the surface. Leakage of subsurface fluids from a wellbore may pose an environmental threat or other undesirable circumstances. Equipment, such as blow out preventers (“BOPs”), which can include annular or spherical BOPs (“SBOPs”), may be positioned about the wellbore to form a seal about a tubular to selectively prevent leakage of fluid as it is brought to the surface. U.S. Pat. No. 4,283,039, entitled Annular Blowout Preventer With Upper And Lower Spherical Sealing Surfaces, purports to disclose one of many annular blowout preventers for use on an oil or gas well. U.S. Pat. No. 8,403,290, entitled Wiper Seal Assembly, purports to describe another of many hydraulically-operated annular blowout preventers for controlling a wellbore and comprising a wiper seal assembly.
BOPs may have selectively operable components, such as pistons or valves, that may be activated to seal and/or sever a tubular in a wellbore. BOPs may include components that wear out or degrade over time, which can cause a BOP not to perform as desired or even to fail. In some cases, contamination of a BOP's hydraulic fluid system, such as by fluid and/or debris from a wellbore, can cause or contribute to reduced performance or failure. Accordingly, it can be desirable to prevent or at least minimize such contamination in order to help ensure proper functionality of BOPs. Various types of pressure seals can be used to provide a physical separation between the fluids in a hydraulic fluid chamber of a BOP and the fluids or other materials in the central bore or bore chamber of a BOP. However, pressure seals can be subject to damage and degradation over time, which may result from exposure to wellbore fluid. As a result, various types of wiper seals (aka wipers or swarf wipers) can be used to help prevent or minimize exposure of pressure seals or other components to wellbore fluid.
The present disclosure is directed to improved wipers for at least partially minimizing exposure of pressure seals or other components to wellbore fluids and to BOPs including the same.